Utilities, including electrical, water, and gas utilities monitor customer consumption through meters. In particular, electrical utilities monitor electrical energy consumption, water utilities monitor water consumption, and gas utilities monitor gas consumption. Utilities use the consumption information primarily for billing, but also for resource allocation planning and other purposes.
Modern utility meters, including electricity meters, typically include numerous solid state electronics components and associated electronic devices including sensor devices, data processors, microcontrollers, memory devices, clocks, and communications devices. These electronic devices are used for various purposes within the meter, including consumption calculation, data storage, and communications. In association with these electronic devices, the utility meters also include a power supply configured to provide DC power to the electronic devices.
A typical onboard power supply utilized in electricity meters is a wide range switching power supply. A single wide range switching power supply may supply the power for the solid state electronics components including data acquisition hardware and communications hardware. Switching power supplies also store DC energy used to sustain operation of the meter for some limited amount of time in the event of a power-down event.
Most utility meters are configured for use with AC power line voltages of 96 Vrms or more (e.g., 96 Vrms to 552 Vrms on the supply line). However, in some instances a utility meter may be connected to a supply line that provides significantly less than 96 Vrms. A low voltage line providing less than 96 Vrms (e.g., a line providing 40 Vrms) may occur when there is a problem with electricity production from the utility provider, with transmission equipment in the power distribution grid, or in substation metering applications outside the U.S. market.